BACKGROUND: Extraperitoneal laparoscopic prostatectomy is an alternative to the intraperitoneal method. However, the effects of extraperitoneal carbon dioxide (CO2) insufflation on hemodynamics and respiratory data have not been adequately studied. This study compared the effects of prolonged intra- and extraperitoneal CO2 insufflation on hemodynamics and gas exchange. METHODS: For this ...

Tautomerism equilibrium of ethyl acetoacetate (EAA) in compressed CO2 + methanol and CO2 + ethanol mixtures was studied by UV-Vis spectroscopy at 308.15 K and different pressures. The volume expansion coefficient (alpha) of the solvents at different pressures was also determined. The relative permittivity (epsilon) of CO2 + methanol and ...

OBJECTIVE: To determine the cardiovascular effects of 60 minutes of abdominal insufflation with CO2 to an intra-abdominal pressure of 15 mm Hg in standing horses receiving a constant rate infusion of detomidine. ANIMALS: 5 horses. PROCEDURE: Horses were randomly allocated into treatment or control groups. A washout period of a ...

We present an experimental point for the carbon equation of state (EOS) at megabar pressures, obtained by laser-driven shock waves. The rear side emissivity of "two-materials two-steps" targets (Al-C) was recorded with space and time resolution and, by applying the impedance mismatch method, allowed a direct determination of relative EOS ...

The possibility to renormalize random walks is used to study numerically the oxygen diffusion and permeation in the acinus, the diffusion cell terminating the mammalian airway tree. This is done in a 3D tree structure which can be studied from its topology only. The method is applied to the human ...

Non-thermal methods of reducing bacterial numbers have been studied for more than a century. A majority of this work has focused on high pressure processing (>100 MPa). The addition of carbon dioxide (CO2) at lower pressures (<100 MPa) is a relatively new process, but has demonstrated similar bactericidal effects. Pressurized ...

This study was designed to evaluate the effects of propofol alone and propofol-clonidine combination on human middle cerebral artery blood flow velocity (Vmca) and cerebrovascular carbon dioxide (CO2) response by using transcranial Doppler ultrasonography. Mean Vmca in response to changes in arterial partial pressure of CO2 (Paco2) was determined under ...

BACKGROUND: Although providing excellent outcome results, laparoscopy also induces particular pathophysiological changes in response to pneumoperitoneum. Knowledge of the pathophysiology of a CO(2) pneumoperitoneum can help minimize complications while profiting from the benefits of laparoscopic surgery without concerns about its safety. METHODS: A review of articles on the pathophysiological changes ...

Carbon stock dynamics was monitored in the Uttara Kannada district, Western Ghats, India, for ten years on eight one-hectare sampling areas belonging to different management and forest categories. The study was initiated in 1984 and the area was monitored until 1994. Our study indicates that, in general, the carbon stock ...

BACKGROUND: We investigated changes in portal venous blood flow (PVBF) during carbon dioxide (CO2) pneumoperitoneum to evaluate the effects of different insufflation profiles and body positions. METHODS: An established rat model was extended by implanting a portal vein flow probe that would enable us to measure PVBF for 60 min ...

The purpose of this study was to verify whether the maximal lactate steady state (MLSS) corresponds to a physiological steady state. Eight male trained subjects performed a 30-min test on a cycle ergometer at a constant power corresponding to their own MLSS which had been previously determined. No significant variation ...

Under supercritical CO2 conditions, simple adjustment of the pressure was found to successfully control the ratio of aldol to enal product in the self-aldol condensation of aldehyde, in which the enal product was obtained in a maximum selectivity of 94% at the critical pressure of 12MPa, whereas 85% selectivity to ...

The aim of the present study was to investigate whether high-pressure carbon dioxide insufflation facilitates mucosal dissection in the transanal endorectal pull-through (TEPT) operation performed in Hirschsprung's disease in a rabbit model. In the study, ten New Zealand rabbits were used. In six of the rabbits, CO(2) under 50 mmHg ...

BACKGROUND: Carbon dioxide pneumoperitoneum induces peritoneal oxidative stress. The aim of this study was to verify the effect of intra-abdominal pressure on oxidative stress in the peritoneum and on post-operative adhesion formation. METHODS: Forty-one rabbits underwent laparoscopic surgery: either gasless, or with CO(2)-pneumoperitoneum at pressures of 5, 10 or 15 ...

PURPOSE: We investigate the impact of extraperitoneal and intraperitoneal CO2 insufflation on cardiopulmonary variables in children undergoing laparoscopic surgery. MATERIALS AND METHODS: The records of 73 patients who underwent laparoscopic urological surgery between December 2000 and April 2002 were retrospectively reviewed. Data collection included respiratory rate (RR), peak airway pressure ...

BACKGROUND: In the morbidly obese patient undergoing laparoscopic gastric bypass (LGBP), insufflation with carbon dioxide to 20 mmHg for prolonged periods may induce significant hypercarbia and acidosis with attendant sequelae. We hypothesize that the use of helium as an insufflating agent results in less hypercarbia and acidosis. METHODS: The study ...

The aim of the current study was to investigate the long-term impact of nocturnal noninvasive (positive-pressure) ventilation (NIV) on sleep, sleep-disordered breathing (SDB) and respiratory function in children and adolescents with progressive neuromuscular disorders (NMD). Thirty patients (12.3 +/- 4.1 yrs) with various inherited NMD were treated with NIV for ...

BACKGROUND: CO2 elimination per breath (VCO2,T) depends primarily on tidal volume (VT). The time course of flow during inspiration influences distribution and diffusive mixing of VT and is therefore a secondary factor determining gas exchange. To study the effect of a postinspiratory pause we defined 'mean distribution time' (MDT) as ...

RATIONALE: The prediction rules for the evaluation of the acid-base status in patients with chronic respiratory acidosis, derived primarily from an experimental canine model, suggest that complete compensation should not occur. This appears to contradict frequent observations of normal or near-normal pH levels in patients with chronic hypercapnia. METHODS: Linear ...

Cardiac output (Q) is a primary determinant of blood pressure and O2 delivery and is critical in the maintenance of homeostasis, particularly during environmental stress. Cardiac output can be determined invasively in patients; however, indirect methods are required for other situations. Soluble gas techniques are widely used to determine Q. ...

BACKGROUND: Increased ventilatory drive, reflected by the slope of increase of ventilation relative to carbon dioxide production (VE/VCO2 slope), has been shown to have a high prognostic value in patients with chronic heart failure (CHF). However, there is no consensus on how to calculate it, as the relation between VE ...

Despite numerous benefits of laparoscopic procedures, the serious hypercapnia and respiratory acidosis in hypercapnic patients with decreased pulmonary compliance during carbon dioxide-induced pneumoperitoneum (CDP) may be developed. Tracheal gas insufflation (TGI) has been shown to be a useful adjunct to controlled mechanical hypoventilation. This study was undertaken to identify whether ...

OBJECTIVE: Noninvasive positive pressure ventilation may be considered a first line intervention to treat patients with hypercapnic respiratory failure. However, CO2 rebreathing from the ventilator circuit or mask may impair CO2 elimination and load the ventilatory muscles. This study was conducted to evaluate the effect of exhalation port location and ...

BACKGROUND: During colonoscopy, air or carbon dioxide is insufflated to secure adequate visualization of the colon, and endoscopy trainees are reminded to use as little gas as possible to avoid patient discomfort. However, the volume of gas insufflated by endoscopists during colonoscopy is unknown. The aim of the present study ...

BACKGROUND: It has been shown repeatedly that laparoscopic cholecystectomy using pneumoperitoneum (CO2 insufflation) may be associated with increased cardiac filling pressures and an increase in blood pressure and systemic vascular resistance. In the present study, the effects on the central circulation during abdominal wall lift (a gasless method of laparoscopic ...

A mathematical model of the variation of partial pressure of carbon dioxide in the arterial blood of a ventilated neonate is developed. The model comprises alveolar, arterial, pulmonary, venous and tissue compartments, with gas exchange in the lung determined by inspiration and expiration terms. Gas exchange is modelled through diffusion ...

We investigated the effect of baroreflex-induced sympathetic activation, produced by lower body negative pressure (LBNP) at -40 mmHg, on cerebrovascular responsiveness to hyper- and hypocapnia in healthy humans. Transcranial Doppler ultrasound was used to measure blood flow velocity (CFV) in the middle cerebral artery during variations in end-tidal carbon dioxide ...

The objective of this prospective clinical study was to evaluate the accuracy of pulse oximetry and capnography in healthy and compromised horses during general anesthesia with spontaneous and controlled ventilation. Horses anesthetized in a dorsal recumbency position for arthroscopy (n = 20) or colic surgery (n = 16) were instrumented ...

BACKGROUND: The indications for laparoscopic surgery have expanded to include diseases possibly associated with peritonitis such as appendicitis, perforated peptic ulcers, and diverticulitis. The safety of carbon dioxide (CO2) pneumoperitoneum in the presence of peritonitis has not been proved. Our previous investigations demonstrated increased bacteremia associated with CO2 insufflation. In ...

BACKGROUND: Abnormal gastric tonometric variables, a surrogate for splanchnic ischemia, occur in approximately 50% of patients at the end of routine cardiac operations and are associated with postoperative morbidity. We sought to determine whether gastric tonometric variables deteriorate after left ventricular assist device insertion and to explore the association between ...

AIMS: The authors, in contrast to similar injuries with open surgery, had observed spontaneous hemostasis of relatively large spleen capsule injuries during laparoscopic surgery. METHODS: Standard spleen injuries were carried out in 5 anesthetized mongrel dogs at different CO2 pressures and in open surgery. Bleeding was checked every minute by ...

REASONS FOR PERFORMING STUDY: Abdominal insufflation is performed routinely during laparoscopy in horses to improve visualisation and facilitate instrument and visceral manipulations during surgery. It has been shown that high-pressure pneumoperitoneum with carbon dioxide (CO2) has deleterious cardiopulmonary effects in dorsally recumbent, mechanically ventilated, halothane-anaesthetised horses. There is no information ...

BACKGROUND: Although evaluation of cardiac output by the partial carbon dioxide rebreathing technique is as accurate as thermodilution techniques under controlled mechanical ventilation, it is less accurate at low tidal volume. It is not clear whether reduced accuracy is due to low tidal volume or low minute ventilation. The effect ...

BACKGROUND: Partial rebreathing is a noninvasive method for measuring pulmonary blood flow (PBF). This study examines the systematic errors produced by the partial rebreathing technique utilizing a comprehensive mathematical model of the cardiorespiratory system of a healthy, 70-kg adult male. METHODS: The model simulates tidal breathing through a branched respiratory ...

Accumulation of carbon dioxide (CO2) can disturb systemic and cerebral hemodynamics in patients receiving electroconvulsive therapy (ECT). The purpose of this study was to identify the effects of end-tidal CO2 monitoring on hemodynamic changes in patients who received ECT under propofol anesthesia. ECT was prescribed to 40 patients under propofol ...

Resting respiratory behavior of Bufo marinus in minimally instrumented toads is described for a period of 24 hours in which the animals are left undisturbed. Torpor-related long apneas are described and their implications for blood gas levels are investigated. Results show that the resting ventilation rate of Bufo marinus is ...

BACKGROUND: Amplitude responsiveness of cerebral blood flow velocity (CBFV) to CO(2) is an established test of cerebrovascular reserve capacity. We aimed to analyze the time course of CBFV during CO(2 )reactivity testing in patients with severe carotid stenosis. METHODS: 87 patients were assigned to three different groups according to the ...

Clonal trees of Pinus radiata D. Don were grown in open-top chambers at a field site in New Zealand for 3 years at ambient (37 Pa) or elevated (65 Pa) carbon dioxide (CO2) partial pressure. Nitrogen (N) was supplied to half of the trees in each CO2 treatment, at 15 ...

PURPOSE: Gas embolism is a rare but well documented entity during operative hysteroscopy, with an incidence of 10-50%. Catastrophic outcomes occur at a rate of three in 17,000 procedures. The purpose of this report is to present a non-fatal case of gas embolism probably caused by the gaseous products of ...

Ventilatory efferent discharges in the isolated central nervous system (CNS) of the lubber grasshopper Taeniopoda eques were recorded and the change of ventilatory rates were measured in correlation to changing concentrations of oxygen and carbon dioxide. These in vitro responses were compared to the ventilatory rates of intact animals exposed ...